The present invention relates to a device for delivering individual ligature wires from a pack of such wires for orthodontics, in which device the ligature wires are inserted in a delivery casing.
The field of orthopedics essentially covers the correction of tooth position and jaw abnormalities. A so-called band-clip apparatus is known, which is used for this purpose. The apparatus makes it possible to correct malpositioned teeth. Brackets are fixed to the labial or lingual surface of the teeth, from which brackets is recessed a locking means for the insertion of a wire clip. In order that the force of the slip be transferred to the teeth, it is necessary to fix the clip to the brackets. This fixing can inter alia also be obtained by fine wires, this procedure being called ligature. The application and fixing of such a wire clip is relatively complicated, particularly if it is necessary to correct both the teeth of the upper and the lower jaw.
For ligatures use is made of very fine wires with a thickness of a few tenths of a millimeter, e.g. 0.2 to 0.3 mm. The wires are placed around the brackets and their ends are twisted for fixing the clip in the lock of a bracket. The ligature wire is placed over the clip and extends below two wings arranged on the brackets and from which it cannot be stripped off. Auxiliary means are used to facilitate the twisting of the ligature wires.
A known device called a twister of the present applicant (Swiss patent application 1894/88 of 19.5.88) makes it possible to twist ligature wires much faster. The device has a rod-like construction and a grip for gripping a ligature wire. The grip is connected to a torsion bar arranged within the rod-like device. Threads are formed on the outer circumference of the torsion bar and these cooperate with the threads of the rod. As a result of an axial movement of the rod, a rotary movement is imparted to the torsion bar and therefore to the grip, through which the ends of the ligature wire are twisted for fixing a clip guided in the brackets so that the clip permits the transfer of its force to the teeth. Although the twisting of the ligature wires is accelerated by the twister, it is not possible to overlook the fact that the insertion of the ligature wire into the twister is difficult and time-consuming. The loop-shaped ligature wires are delivered in boxes resting in random manner on one another. It constitutes a very time-consuming process to remove a single ligature wire from a plurality of such wires which are in part hung up on one another.